Saws

Milwaukee M12 Hackzall

The Hackzall is small enough to tuck into a tool pouch and light enough to use one-handed.

I've been using the Milwaukee 2420-22 Hackzall kit in my remodeling and deck-building business since late last summer. Designed for light cutting, this miniaturized recip saw takes the same 12-volt lithium ion batteries that the M12-series screwdriver and impact driver use.

The Hackzall has a grip with an unusual shape. It looks more like a drill's grip than a recip saw's. I liked the tool's comfortable feel and handy size right away. It's small enough to use in tight quarters where a full-size model wouldn't fit, and I can stuff it in a toolbelt when I'm climbing a ladder.

The saw has a variable-speed trigger and an LED task light that shines on the work area, and comes in a blow-molded case with a 30-minute charger and two batteries.

Capabilities
The Hackzall is not a substitute for a full-size cordless or corded recip saw. With its 1/2-inch nonorbital stroke and tiny battery, it hasn't got the power to effectively cut 2-by lumber or multilayered materials like roofing, siding, and flooring. Instead, it's useful for light-duty cuts — the kind often performed by hand — and the occasional heavy cut that would be inconvenient to do with a larger saw.

Drywall. The Hackzall is the perfect replacement for the keyhole saws used to cut openings in drywall. It cuts faster than I could ever hope to cut by hand, with less effort and no more dust. Within weeks it had earned a permanent spot as part of my drywall tool arsenal.

Sheet goods. The Hackzall is good for cutting plywood and sheet goods. With a fresh blade, it cuts quickly and precisely through everything from 1/8-inch hardboard to 3/4-inch CDX. At one point I found myself keeping the saw in my toolbelt while retrofitting a plywood subfloor in an old house; that way, I could notch and fit the sheets my cut man was carrying up the stairs. The tool is so small and light I was able to hold sheets on edge and cut them one-handed, eliminating the need to use sawhorses in a crowded space.

Miscellaneous tasks. Although the Hackzall will cut through studs and dimensional lumber, it's slow at this task and the battery runs down quickly. I eventually decided that if I needed to cut more than two or three studs, I'd just go out to my van to get a full-size saw.

The same held true for composite decking. Since my company installs a lot of decks, I'd hoped to use this tool instead of my corded jigsaw to cut notches. But it was not to be — the Hackzall is miserably slow at cutting dense materials.

On the other hand, the plumber and the electrician who were working on one of my jobs found the saw invaluable. After lending it to them, I had a hard time getting it back. It could handle most of the tasks they encounter on service calls — such as cutting small access holes, EMT, and pipe.

Battery Life
According to Milwaukee, the Hackzall can make 80 cuts in 1 1/2-inch PVC pipe on a single charge. To find out if this was true, I counted the number of cuts the saw could make in that material with a freshly charged battery and a new 6-inch PVC blade. The saw began to slow down after 35 cuts; after 43, the battery was dead.

I performed a similar test by cross-cutting Douglas fir 2x4s with a general-purpose blade. The lumber was very hard and dry, and the battery was depleted after nine cuts (31 1/2 total inches). The saw didn't slow down — it just quit.

In both tests, the runtime turned out to be less than the manufacturer promised. Still, for a saw that runs on a little 12-volt battery, I think it performed pretty well.

Blades
The keyless clamp on the Hackzall accepts standard-thickness recip-saw blades, but you'll get better results with the thinner kerf blades made specifically for the tool. Standard blades also run the battery down more quickly. However, I have one complaint about these thin kerf blades: As of late 2008 they were impossible to find in local stores. They can be ordered online or by phone, but sometimes I need them right away.

The Bottom Line
Although it's not a necessity, the Hackzall is definitely handy to have around. It doesn't do anything faster or better than a full-size model — but it offers the advantage of being light, portable, and easy to use one-handed. And for a tool junkie like me, those are great reasons to have one in my toolbox.